In electronic apparatuses such as communication apparatuses, band-pass filters that allow only electric signals of a specific frequency to pass therethrough are used. In particular, band-pass filters are widely used in which a passband including an even mode resonance frequency and an odd mode resonance frequency is formed by using even mode resonance and odd mode resonance in a resonance system in which two resonators having the same resonance frequency are electromagnetically coupled to each other. In such band-pass filters, the difference between the even mode resonance frequency and the odd mode resonance frequency changes in response to the strength of the electromagnetic coupling between the two resonators, thereby determining the width of the passband (e.g., see Patent Literature 1).